<!DOCTYPE html>
<html>

<head>
    <title>ScalarField / Geotiff</title>
    <meta name="viewport" content="width=device-width, initial-scale=1.0, maximum-scale=1.0, user-scalable=no" />
    <link rel="stylesheet" href="//unpkg.com/leaflet@1.2.0/dist/leaflet.css" />
    <link rel="stylesheet" href="examples.css" />

    <link href="https://fonts.googleapis.com/css?family=Roboto:100,400" rel="stylesheet">
</head>

<body>
    <h1 class="title mapTitle">ScalarField GeoTIFF</h1>
    <div id="map"></div>

    <!-- CDN -->
    <script src="//d3js.org/d3.v4.min.js"></script>
    <script src="//npmcdn.com/leaflet@1.2.0/dist/leaflet.js"></script>
    <script src="//npmcdn.com/geotiff@0.3.6/dist/geotiff.js"></script>
    <script src="//cdnjs.cloudflare.com/ajax/libs/chroma-js/2.1.0/chroma.min.js"></script>

    <!-- Plugin -->
    <script src="dist/leaflet.canvaslayer.field.js"></script>

    <script>
        let map = L.map('map');

        /* Dark basemap */
        let url = 'https://cartodb-basemaps-{s}.global.ssl.fastly.net/dark_nolabels/{z}/{x}/{y}.png';
        L.tileLayer(url, {
            attribution: '&copy; <a href="http://www.openstreetmap.org/copyright">OpenStreetMap</a> contributors, &copy; <a href="https://carto.com/attributions">CARTO</a>',
            subdomains: 'abcd'
        }).addTo(map);

        /* NASA NDVI Index (2017-02) 0.1 deg (3600 x 1800): ~3.3MB with LZW (24.7MB uncompressed)
        https://neo.sci.gsfc.nasa.gov/view.php?datasetId=MOD13A2_M_NDVI
        */
        d3.request("data/ndvi_201702_LZW.tif").responseType('arraybuffer').get(
            function (error, tiffData) {
                let ndvi = L.ScalarField.fromGeoTIFF(tiffData.response);

                let layer = L.canvasLayer.scalarField(ndvi, {
                    color: chroma.scale('YlGn').domain(ndvi.range),
                    inFilter: (v) => v !== 0
                }).addTo(map);

                layer.on('click', function (e) {
                    if (e.value !== null) {
                        let v = e.value.toFixed(2);
                        let html = (`<span class="popupText">NDVI ${v}</span>`);
                        let popup = L.popup()
                            .setLatLng(e.latlng)
                            .setContent(html)
                            .openOn(map);
                    }
                });
                map.fitBounds(layer.getBounds());

            });
    </script>
</body>

</html>